I agree that email is an excellent means to communicate with both vendors and clients.  You can even set it up so that it dings or flashes when a new email comes in.  And as long as you use some kind of spam guard and are not constantly receiving audible notices that your cheap Viagra email has arrived, you will know that the message may be urgent and should be checked.

Many independent abstractors may not have access to email while in the field.  They should provide some means to reach them if they intend to remain competitive--at minimum, a cell phone with frequently checked voice mail.

Your clients, who likely have an office staff, will provide you with means to reach them if they are serious about communication.  They should have enough fax lines to handle the incoming volume, provide their extension or direct line and/or their email address and express to you their preferred method of communication.